Steering column for a motor vehicle

Abstract

A steering column may include an adjustment unit with a steering spindle that is mounted rotatably about its longitudinal axis in a casing tube, a supporting unit that supports the adjustment unit, and a clamping device that controls movement between the adjustment unit and the supporting unit in a longitudinal direction. The clamping device may comprise an actuating element that interacts with a clamping mechanism for clamping the supporting unit to the adjustment unit. The clamping device may further comprise a locking part. In the securing position a form-fitting element of the locking part engages non-displaceably in the longitudinal direction with a form-fitting element of an engagement part connected to the adjustment unit. In the release position the form-fitting element of the locking part may be spaced apart from the form-fitting element of the engagement part to release the adjustment unit. The actuating element may be connected to a lifting mechanism separate from the clamping mechanism. The lifting mechanism may be connected to the locking part and may convert actuation of the actuating element into a working stroke of the locking part. The working stroke of the lifting mechanism is assignable independently of a clamping stroke of the clamping mechanism.

What is claimed is: 
     
       1. A steering column for a motor vehicle comprising:
 an adjustment unit with a steering spindle that is mounted rotatably in a casing tube so as to be rotatable about a longitudinal axis of the steering spindle; 
 a supporting unit that is connectable to a body of the motor vehicle, wherein the adjustment unit is configured to be accommodated in the supporting unit; 
 a clamping device, wherein in a securing position the clamping device secures the adjustment unit relative to the supporting unit in normal operation, wherein in a release position the clamping device permits movement of the adjustment unit relative to the supporting unit at least in a longitudinal direction, the clamping device comprising:
 an actuating element that interacts with a clamping mechanism that converts an actuation of the actuating element into a clamping stroke directed transversely to the longitudinal axis for clamping the supporting unit to the adjustment unit, and 
 a locking part that is supported in the longitudinal direction on the supporting unit, wherein in the securing position a form-fitting element of the locking part engages non-displaceably in the longitudinal direction with a form-fitting element of an engagement part connected to the adjustment unit, wherein in the release position the form-fitting element of the locking part is spaced apart from the form-fitting element of the engagement part, thereby permitting movement of the adjustment unit relative to the supporting unit in the longitudinal direction; 
 
 an energy absorption device that connects the engagement part to the adjustment unit; and 
 a lifting mechanism that is connected to the actuating element and is separate from the clamping mechanism, wherein the lifting mechanism is connected to the locking part and converts the actuation of the actuating element into a working stroke of the locking part relative to the engagement part, wherein the working stroke of the lifting mechanism is assignable independently of the clamping stroke of the clamping mechanism. 
 
     
     
       2. The steering column of  claim 1  wherein the working stroke of the lifting mechanism is oriented transversely to the clamping stroke of the clamping mechanism. 
     
     
       3. The steering column of  claim 1  wherein the actuating element is configured as a clamping axle that extends transversely to the longitudinal direction and is rotatable about an axis of the clamping axle for the actuation of the clamping device, wherein a radially projecting cam is disposed on the clamping axle in a rotationally-fixed manner, wherein the locking part comprises a coupling section with a control face positioned parallel to the clamping axle, wherein a cam contour of a cam is configured to operatively engage with the control face of the coupling section of the locking part. 
     
     
       4. The steering column of  claim 3  further comprising a spring element disposed between the cam contour of the cam and the control face of the coupling section of the locking part. 
     
     
       5. The steering column of  claim 3  wherein the form-fitting element of the engagement part is configured as a plate and is oriented parallel to the axis of the clamping axle and parallel to the longitudinal axis. 
     
     
       6. The steering column of  claim 3  wherein the control face is configured as a lifting surface, wherein a surface normal of the lifting surface points in a direction of engagement of the form-fitting elements of the locking part and of the engagement part. 
     
     
       7. The steering column of  claim 3  wherein the control face is configured as a pressing surface, wherein a surface normal of the pressing surface points in a direction contrary to engagement of the form-fitting elements of the locking part and of the engagement part. 
     
     
       8. The steering column of  claim 1  further comprising a spring element disposed between a cam contour of a cam and a control face. 
     
     
       9. The steering column of  claim 1  further comprising a guide formed on the supporting unit, wherein the locking part is displaceably guided in the guide in a direction of the engagement part. 
     
     
       10. The steering column of  claim 1  wherein the form-fitting elements are configured as serrations.